1. Field of the Invention
The present general inventive concept relates to an image forming apparatus. More particularly, the present general inventive concept relates to an image forming apparatus to use an intermediate transfer belt.
2. Description of the Related Art
Generally, an image forming apparatus to use an intermediate transfer belt has four image forming units so that it overlappingly transfers images formed on each of the four image forming units onto the intermediate transfer belt to form full color images.
FIGS. 1 and 2 are a partial perspective view illustrating a conventional image forming apparatus.
Referring to FIGS. 1 and 2, a conventional image forming apparatus 1 includes an engine frame 10, four toner cartridges 13, four image forming units 14, an intermediate transfer belt unit 20, and a supporting cover 30.
The engine frame 10 supports the four toner cartridges 13, the four image forming units 14, the intermediate transfer belt unit 20, and the supporting cover 30. Around the engine frame 10 are disposed a printing medium feeding unit (not illustrated) that holds and feeds printing media, a printing medium moving unit (not illustrated) to move a printing medium, a transferring unit (not illustrated) to transfer color images formed on the intermediate transfer belt onto the printing medium, a fusing unit (not illustrated) to fuse the transferred images onto the printing medium, and a discharging unit (not illustrated) to discharge the fused printing medium outside.
Each of the four toner cartridges 13 holds a different color toner to develop electrostatic latent images formed on each of the image forming units 14. In general, the four toner cartridges 13 hold black, yellow, magenta, and cyan toners, respectively.
Each of the four image forming units 14 forms predetermined images corresponding to printing data and includes a photosensitive medium (not illustrated), a charging unit (not illustrated) to charge a surface of the photosensitive medium with a predetermined voltage, an exposure unit (not illustrated) to form electrostatic latent images on the surface of the photosensitive medium, and a developing unit (not illustrated) to develop the electrostatic latent images formed on the photosensitive medium with toner supplied from the toner cartridge 13.
The intermediate transfer belt unit 20 supports an intermediate transfer belt 21 to move endlessly in a closed loop, and includes the intermediate transfer belt 21 and an intermediate transfer belt frame 23. Four transfer backup rollers (not illustrated) are disposed in positions corresponding to the photosensitive media of the four image forming units 14 inside the intermediate transfer belt 21.
A fixing lever 40 is disposed at the engine frame 10 at a side of the transfer backup roller to transfer black toner images from the photosensitive medium to the intermediate transfer belt 21. When turning the fixing lever 40 in a first direction, the fixing lever 40 presses the transfer backup roller to cause the intermediate transfer belt 21 to come in contact with the photosensitive medium of the image forming unit 14a, to form the black toner images. Then, the images on the photosensitive medium are transferred to the intermediate transfer belt 21. However, in this state, when separating the image forming unit 14a, the photosensitive medium thereof rubs against the intermediate transfer belt 21 so that damages such as scratches may occur at the surfaces of the photosensitive medium and the intermediate transfer belt 21.
When turning the fixing lever 40 in a second direction, the transfer backup roller is released from the fixing lever 40 so that the intermediate transfer belt 21 comes apart from the photosensitive medium. In this state, when separating the image forming unit 14a, the photosensitive medium thereof does not rub against the intermediate transfer belt 21 so that no damages occur at the surfaces of the photosensitive medium and the intermediate transfer belt 21.
The supporting cover 30 rotatably supports a shaft 15 of each of the four photosensitive media so that the four photosensitive media of the image forming units 14 can maintain predetermined intervals therebetween and rotate. Two locking levers 32 are disposed at an outer surface of the supporting cover 30. Two locking brackets 12 are disposed at positions of the engine frame 10 corresponding to the two locking levers 32. Therefore, the supporting cover 30 is pushed against the side of the engine frame 10, and then, the two locking levers 32 are turned to hook the locking brackets 12 so that the supporting cover 30 is fixed to the engine frame 10. Also, the locking levers 32 are turned in a reverse direction to escape from the locking brackets 12 so that the supporting cover 30 can be separated from the engine frame 10.
However, the conventional image forming apparatus 1 is configured so that the locking levers 32 to fix the supporting cover 30 to the engine frame 10 and the fixing levers 40 to cause the intermediate transfer belt 21 to contact the photosensitive medium operate separately.
As a result, in order to separate the image forming unit 14 from the engine frame 10, the locking levers 32 and the fixing levers 40 are required to be operated separately. In other words, the two locking levers 32 are turned, and then, the supporting cover 30 is separated from the engine frame 10 so that the fixing levers 40 are exposed as illustrated in FIG. 2. After that, when turning the fixing levers 40, the intermediate transfer belt 21 comes apart from the photosensitive medium. In this state, when the image forming unit 14a is separated, the photosensitive medium thereof does not rub against the intermediate transfer belt 21 so that no damage occurs.
After mounting the image forming unit 14a, the supporting cover 30 is mounted in the opposite of the above described procedure. In other words, after the image forming unit 14a is mounted, the fixing levers 40 are turned to cause the intermediate transfer belt 21 to come in contact with the photosensitive medium. After that, the supporting cover 30 is pushed against the engine frame 10, and then, the locking levers 32 are turned so that the supporting cover 30 is fixed to the engine frame 10.
In the conventional image forming apparatus 1, when replacing or maintaining the image forming unit 14a, it is required to turn the locking levers 32 and the fixing lever 40 in order. Therefore, users experience inconvenience when replacing or maintaining the image forming unit 14a. 